Stress sensitive devices, such as optical devices (e.g. photo detectors, CCDs, LCD, photodiodes), microelectromechanical systems (e.g. spatial light modulators using micromirrors) may suffer from device failure due to warping and stresses induced either during device packaging processes or in operation after improper packaging processes. In a typical packaging process, the device is attached to a package substrate for holding the device. When the coefficient of thermal expansion (CTE) of the package substrate does not match the device substrate that contacts the package substrate, the device will be warped, resulting in device failure.
An approach to solve this problem is to select device substrate and package substrate having the same or similar CTEs. However, this is not achievable in many situations because the selection of the device substrate and also the package substrate need to satisfy other requirements with higher priority.
Therefore, a method is desired for packaging stress sensitive devices with a low stress assembly process, while allows for employing a wide range of adhesives and packaging materials.